I have in my garage a plumb line (pictured above), inherited from either my dad or granddad, I can’t remember. I used it for a project once and forgot to return it—how’s that for grateful? The plumb line consists of a heavy metal weight (the plumb bob) attached to a string. When hung and steadied it makes a vertical reference line. You can tell if the wall you’re building is straight or leaning.

The plumb line is a simple, effective, inexpensive, and ancient tool.

Isaiah used the plumb line to describe a coming age of justice, ushered in by the Lord. See, I lay in Zion, a tested stone, a precious cornerstone for a sure foundation; the one who relies on it will never be stricken with panic, I will make justice the measuring line and righteousness the plumb line.

The coming Messiah is that cornerstone. Using construction techniques, Isaiah lays out a building with a secure foundation. Its measurements conform to justice and a plumb line sets the walls of righteousness.

In other words, when Jesus returns all things shall be made right. The lines of justice and righteous will form a solid structure. As Isaiah goes on to write, all this comes from the Lord Almighty, whose plan is wonderful, and whose wisdom is magnificent.

I trust in the promise that someday, a plumb line in the hand of the Lord will straighten the injustices of the world. But I recognize that one of our roles as image bearers of God involves working the plumb line as well, opposing injustice and undergirding righteousness wherever we find it.

Isaiah 28 in week thirty-five of reading the Bible cover to cover